This present invention relates to a projector with controls for the slide changer and to the associated stop of the slide changer, where the slide changer has independently acting insertion and storage feeder arms for the changing system and at least two routes for inserting and ejecting the slides.
The state of the art of slide changing equipment for magazine slide projectors may be ascertained by reference to U.S. Pat. No. 3,910,696 Hans Mulch which issued Oct. 7, 1975, the disclosure of which is incorporated herein.
U.S. Pat. No. 3,910,696 discloses a system comprising independently acting slide feeder arms actuated by controls, where one of these arms inserts the slide into the slide stage and the other returns it by a special route to storage. Slide changing in this system takes place so that with insertion of a new slide, the previous slide is removed from the slide stage. This patent further discloses that a stop may be provided for the changing system to prevent defocusing when changing. However, this disclosure does not specify either the design or the operation. It must be assumed therefore that the stop control of U.S. Pat. No. 3,910,696 is conventional.
Stop control is generally accomplished by controlling the stops by the slides themselves or by a component moving the slides. This ensures that at the beginning of slide removal, and so long as it remains wholly or partly within the projection window, the stop is closed and reopens only when the new slide is in its final position.
However, all of these prior art systems suffer from the limitation that there is a relatively long dark pause between the individual projections. This is disadvantageous to an annoying degree for the viewer because the eye must constantly readapt. The viewer therefore tires rapidly.
If on the other hand there is no stop, so that the prior art system remains open, a wiper effect occurs between the individual slide changes, which is unpleasant and disrupting.